RISKS: DEPRESSION LINKED TO LATER DEMENTIA

A new study suggests that people with depression are significantly more likely to develop dementia later in life.

The analysis, published July 6 in the journal Neurology, followed 949 participants in the famous Framingham Heart Study over an average of eight and a half years, some for as long as 17 years.

In that time, more than 17 percent — 164 participants — developed dementia. But among those who were depressed when the study started, the rate was much higher: almost 22 percent.
Adjusting for differences between groups, researchers found that depression raised the risk of dementia by 72 percent. And the more severe the depression, the greater the risk of dementia later.

The lead author, Dr. Jane Saczynski, an assistant professor at the University of Massachusetts Medical School in Worcester, suggested that the vascular changes in the brain associated with depression might also lead to dementia. Given the study’s long interval, she said, “it is very clear that depression is a risk factor for dementia rather than a consequence of the disease.”

A version of this article appeared in print on July 20, 2010, on page D6 of the New York edition.